U.S. patent application number 12/692235 was filed with the patent office on 2011-07-28 for keypad device having a removable button assembly.
This patent application is currently assigned to LUTRON ELECTRONICS CO., INC.. Invention is credited to Brian R. O'Donnell.
Application Number | 20110181446 12/692235 |
Document ID | / |
Family ID | 44308558 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110181446 |
Kind Code |
A1 |
O'Donnell; Brian R. |
July 28, 2011 |
Keypad Device Having a Removable Button Assembly
Abstract
A control device, such as a keypad device, for use in a load
control system for controlling the power delivered from an AC power
source to an electrical load comprises a switch, a yoke fixedly
mounted with respect to the switch, and a removable button assembly
that may be removed from the control device. The removable button
assembly comprises a spring tree having a frame portion and at
least one button pivotably coupled to the frame portion. The button
assembly is received within a channel of the yoke and is positioned
such that the button is operable to actuate the switch when the
button is pressed. The button assembly is adapted to slide through
the channel, such that the button assembly may be removed from the
control device. Accordingly, the button of the control device may
be easily changed after installation of the control device.
Inventors: |
O'Donnell; Brian R.;
(Alburtis, PA) |
Assignee: |
LUTRON ELECTRONICS CO.,
INC.
Coopersburg
PA
|
Family ID: |
44308558 |
Appl. No.: |
12/692235 |
Filed: |
January 22, 2010 |
Current U.S.
Class: |
341/22 |
Current CPC
Class: |
H01H 13/76 20130101;
H01H 2233/04 20130101 |
Class at
Publication: |
341/22 |
International
Class: |
H03M 11/00 20060101
H03M011/00 |
Claims
1. A control device for use in a load control system for
controlling the power delivered from an AC power source to an
electrical load, the control device comprising: a switch; a yoke
fixedly mounted with respect to the switch, the yoke comprising a
channel; and a removable button assembly comprising a spring tree
having a frame portion and at least one button pivotably coupled to
the frame portion, the button assembly received within the channel
of the yoke and positioned such that the button is operable to
actuate the switch when the button is pressed, the button assembly
adapted to slide through the channel, such that the button assembly
may be removed from the control device.
2. The control device of claim 1, further comprising: a printed
circuit board fixedly mounted to the yoke; wherein the mechanical
switch comprises a tactile switch mounted on the printed circuit
board.
3. The control device of claim 2, wherein the spring tree further
comprises a snap having an opening receiving a snap tab formed in
the yoke, such that the spring tree is locked in place when the
snap tab is received in the opening of the snap.
4. The control device of claim 3, wherein the snap is coupled to
the frame portion of the spring tree via cantilevered spring arms,
such that the snap is operable to pivot with respect to the frame
portion.
5. The control device of claim 4, wherein the snap may be pulled
away from the yoke, such that the opening of the snap is decoupled
from the snap tab and the button assembly may be slid through the
channel of the yoke and removed from the control device.
6. The control device of claim 5, wherein the snap tab comprises a
sloped surface and an end surface, the snap adapted to contact the
sloped surface of the snap tab when the button assembly is being
installed on the keypad device and the spring tree is being slid
through the channel towards the snap tab, such that snap pivots
about the spring arms and translates across the sloped surface
until the snap tab is received in the opening of the snap, the end
surface of the snap tab adapted to contact the edges of the opening
to lock the button assembly in place.
7. The control device of claim 6, wherein the yoke further
comprises a biasing member pivotably coupled to the channel and
operable to push the spring tree in a direction, such that an edge
of the opening contacts the end surface of the snap tab.
8. The control device of claim 2, wherein the channel of the yoke
comprises a plurality of tabs and a plurality of supports, the
frame portion of the spring tree received between the tabs and the
supports.
9. The control device of claim 8, wherein the channel of the yoke
comprises a plurality of extensions, the frame portion of the
spring tree adapted to break through the extensions and to be held
in place by the remaining portions of the extensions.
10. The control device of claim 9, wherein the extensions are
located adjacent the supports of the yoke, such that the frame
portion of the spring tree is held in place between the remaining
portions of the extensions and the adjacent supports.
11. The control device of claim 8, wherein the yoke comprises
sloped structures for guiding the frame portion of the spring tree
to be received between the tabs and the supports.
12. The control device of claim 2, wherein the spring tree is made
from a conductive material, the control device further comprising
at least one ESD conduction post made from a conductive material
and coupled between the spring tree and the printed circuit board
for conducting energy from an ESD event to a ground connection.
13. The control device of claim 1, wherein the control device
comprises a keypad device.
14. The control device of claim 13, wherein the button assembly
comprises a plurality of buttons.
15. The control device of claim 14, wherein the plurality of
buttons are arranged in a column on the keypad device.
16. The control device of claim 14, further comprising: a second
button assembly received within a second channel of the yoke and
having a plurality of buttons; wherein the two button assemblies
are arranged as two columns on the keypad device.
17. The control device of claim 13, wherein the keypad device
comprises a wall-mounted keypad.
18. A wall-mounted keypad device for use in a load control system
for controlling the power delivered from an AC power source to an
electrical load, the keypad device comprising: a yoke adapted to be
mounted to an electrical wallbox, the yoke comprising a channel; a
printed circuit board fixedly mounted to the yoke; a tactile switch
mounted to the printed circuit board; and a removable button
assembly comprising a spring tree having a frame portion and at
least one button pivotably coupled to the frame portion, the button
assembly received within the channel of the yoke and positioned
such that the button is operable to actuated the tactile switch
when the button is pressed, the button assembly adapted to slide
through the channel, such that the button assembly may be removed
from the keypad device.
19. The control device of claim 18, wherein the spring tree further
comprises a snap coupled to the frame portion of the spring tree
via cantilevered spring arms allowing the snap to pivot with
respect to the frame portion, the snap having an opening receiving
a snap tab formed in the yoke for locking the spring tree in
place.
20. The control device of claim 18, wherein the channel of the yoke
comprises a plurality of tabs and a plurality of supports, the
frame portion of the spring tree received between the tabs and the
supports, the channel of the yoke further comprising a plurality of
extensions, the frame portion of the spring tree adapted to break
through the extensions and to be held in place by the remaining
portions of the extensions.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a control device of a load
control system for controlling the amount of power delivered from
an alternating-current (AC) power source to a plurality of
electrical loads, and more particularly, to a keypad device having
a removable button assembly.
[0003] 2. Description of the Related Art
[0004] Typical load control systems are operable to control the
amount of power delivered to an electrical load, such as a lighting
load or a motor load, from an alternating-current (AC) power
source. A load control system generally comprises a plurality of
control devices coupled to a communication link to allow for
communication between the control devices. The load control system
includes load control devices operable to control the amount of
power delivered to the loads in response to digital messages
received via the communication link or from local inputs, such as
user actuations of a button. An example of a lighting control
system is described in greater detail in commonly-assigned U.S.
Pat. No. 6,803,728, issued Oct. 12, 2004, entitled SYSTEM FOR
CONTROL OF DEVICES, the entire disclosure of which is hereby
incorporated by reference.
[0005] Typical prior art load control systems often include one or
more keypad devices, which each include a plurality of buttons for
receiving user inputs to the load control system. The keypad
devices transmit digital messages across the communication link to
control the loads coupled to the load control devices in response
to actuations of the buttons. In order to identify the function to
be performed by any particular button, identifiers (such as
descriptive icons or text) are often provided on the buttons of
keypad devices. For example, the identifiers may be engraved on the
buttons. It may be desirable to change or update the identifiers
provided on the buttons after installation of the keypad devices.
Therefore, there is a need for a method of easily changing the
buttons of a keypad device after installation of the keypad
device.
SUMMARY OF THE INVENTION
[0006] According to an embodiment of the present invention, a
control device for use in a load control system for controlling the
power delivered from an AC power source to an electrical load
comprises a switch, a yoke fixedly mounted with respect to the
switch, and a removable button assembly that may be removed from
the control device. The removable button assembly comprises a
spring tree having a frame portion and at least one button
pivotably coupled to the frame portion. The button assembly is
received within a channel of the yoke and is positioned such that
the button is operable to actuate the switch when the button is
pressed. The button assembly is adapted to slide through the
channel, such that the button assembly may be removed from the
control device.
[0007] Other features and advantages of the present invention will
become apparent from the following description of the invention
that refers to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention will now be described in greater detail in the
following detailed description with reference to the drawings in
which:
[0009] FIG. 1 is a perspective view of a keypad device according to
an embodiment of the present invention;
[0010] FIG. 2 is a perspective view of the keypad device of FIG. 1
with a faceplate removed showing two button assemblies of the
keypad device;
[0011] FIG. 3 is a perspective view of the keypad device of FIG. 1
with one of the button assemblies partially removed;
[0012] FIG. 4 is a perspective view of one of the button assemblies
and the keypad device of FIG. 3 having both of the button
assemblies completely removed;
[0013] FIG. 5 is a right-side cross-sectional view of the keypad
device of FIG. 1 with both of the button assemblies fully
installed;
[0014] FIG. 6 is an exploded perspective view of the keypad device
of FIG. 1;
[0015] FIG. 7 is a bottom cross-sectional view of the keypad device
of FIG. 1 with both of the button assemblies fully installed;
[0016] FIG. 8A is a perspective cross-sectional view of a yoke of
the keypad device of FIG. 1;
[0017] FIG. 8B is an enlarged section of the perspective view of
FIG. 8A;
[0018] FIG. 9A is a perspective cross-sectional view of the yoke of
FIG. 8A with the button assemblies installed; and
[0019] FIG. 9B is an enlarged section of the perspective view of
FIG. 9A.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The foregoing summary, as well as the following detailed
description of the preferred embodiments, is better understood when
read in conjunction with the appended drawings. For the purposes of
illustrating the invention, there is shown in the drawings an
embodiment that is presently preferred, in which like numerals
represent similar parts throughout the several views of the
drawings, it being understood, however, that the invention is not
limited to the specific methods and instrumentalities
disclosed.
[0021] FIG. 1 is a perspective view of a wall-mountable keypad
device 100 according to an embodiment of the present invention. The
keypad device 100 may be used as part of a load control system
having one or more load control devices (not shown) for controlling
the amount of power delivered to a plurality of electrical loads
(not shown), such as lighting loads or motor loads. The keypad
device 100 may be wall-mounted to a standard electrical wallbox
(not shown). The keypad device 100 comprises a faceplate 110 and a
plurality of buttons 112 (e.g., six buttons). In response to
actuations of the buttons 112, the keypad device 100 may transmit
digital messages to the load control devices of the load control
system via a communication link, for example, a wired communication
link or a wireless communication link, such as a radio-frequency
(RF) communication link or an (IR) communication link. The load
control devices are operable to adjust the amount of power being
delivered to the electrical loads in response to receiving the
digital messages from the keypad device 100. Each of the buttons
112 of the keypad device 100 comprises a visual indicator 114,
which may be illuminated to provide feedback of the status of the
electrical loads of the load control system. Examples of load
control systems are described in greater detail in co-pending,
commonly-assigned U.S. patent application Ser. No. 11/703,912,
filed Feb. 8, 2007, entitled METHOD OF TRANSMITTING A HIGH-PRIORITY
MESSAGE IN A LIGHTING CONTROL SYSTEM, and U.S. patent application
Ser. No. 12/033,223, filed Feb. 19, 2008, entitled COMMUNICATION
PROTOCOL FOR A RADIO-FREQUENCY LOAD CONTROL SYSTEM, the entire
disclosures of which are hereby incorporated by reference.
[0022] FIG. 2 is a perspective view of the keypad device 100 with
the faceplate 110 removed. The keypad device 100 comprises an
adapter 116 having attachment openings 118. The rear surface of the
faceplate 110 comprises snaps (not shown) which are received in the
attachment openings 118 of the adapter 116, such that the faceplate
may be attached to the keypad device 100 without screws. The
adapter 116 is connected to a mounting yoke 120 of the keypad
device 100 via screws 122 received in screw openings 124 (FIG. 3)
of the yoke. The yoke 120 allows the keypad device 100 to be
mounted to the electrical wallbox via screws (not shown) received
through mounting openings 126 of the yoke.
[0023] According to the embodiment of the present invention, the
keypad device 100 comprises two removable button assemblies 130.
Each button assembly 130 comprises one column of buttons 112 of the
keypad device 100 (i.e., three buttons), and a spring tree 132, to
which the buttons are mounted. FIG. 3 is a perspective view of the
keypad device 100 with the adapter 116 removed and one of the
button assemblies 130 partially removed. FIG. 4 is a perspective
view of one of the button assemblies 130 and the keypad device 100
having both of the button assemblies completely removed. FIG. 5 is
a right-side cross-sectional view of the keypad device 100 with the
button assemblies 130 installed, but without the faceplate 110 and
the adapter 116 (taken through the line shown in FIG. 2).
[0024] When the button assemblies 130 are fully installed on the
keypad device 100 and one of the buttons 112 is pressed, the button
actuates a respective mechanical tactile switch 134 mounted on a
printed circuit board (PCB) 135 of the keypad device. The printed
circuit board 135 is fixedly mounted to the yoke 120, such that the
buttons 112 are positioned immediately above the tactile switches
134 when the button assemblies 130 are installed. As shown in FIG.
4, the keypad device 100 also comprises a plurality of
light-emitting diodes (LEDs) 136, which are also mounted to the
printed circuit board 135 and operate to illuminate the visual
indicators 114 on each of the buttons 112.
[0025] FIG. 6 is an exploded perspective view of the keypad device
100 showing the spring trees 132, the yoke 120, and the printed
circuit board 135 in greater detail. When a user actuates a button
112 of the keypad device 100, the user may discharge built-up
static electricity to the keypad device, i.e., an electro-static
discharge (ESD) event may occur. When an ESD event occurs, the
energy is typically coupled to the spring trees 132 of the keypad
device 100 (which are made from a conductive material, such as, for
example, stainless steel), and is conducted to ground through the
lowest impedance path available in the electrical circuitry of the
keypad device. The energy from ESD events may damage the electrical
circuitry of the keypad device 100 if the circuitry is not
protected appropriately. To provide a low-impedance path to ground,
the keypad device 100 comprises ESD conduction posts 137 that are
located within ESD conduction apertures 138 in the yoke 120 and are
also made from a conductive material (e.g., stainless steel). When
the printed circuit board is connected to the yoke 120 and the
button assemblies 130 are fully inserted on the keypad device 100,
a first end of each conduction post 137 is located adjacent one of
the spring trees 132 and a second end of each conduction post is
located adjacent one of two conductive pads 139 on the printed
circuit board 135. The conductive pads 139 may be directly
electrically coupled to or capacitively coupled to the ground
connection of the external power source of the keypad device 100.
Therefore, the ESD conduction posts 137 provide low-impedance paths
to ground that are not through the electrical circuitry of the
keypad device 100, such that the electrical circuitry may not be
damaged during ESD events.
[0026] FIG. 7 is a bottom cross-sectional view of the yoke 120 with
both of the button assemblies 130 installed (taken through the line
shown in FIG. 2) showing how the buttons 112 are attached to the
spring trees 132. Each of the buttons 112 is attached to a
respective spring plate 140 (FIG. 6) of the spring trees 132.
Specifically, each button 112 comprises two attachment posts 142
that are received through attachment openings 144 of the spring
plates 140 of the spring tree 132. The attachment openings 144
comprise fingers that operate to permanently affix the buttons 112
to the spring trees 132. Each button 112 comprises an actuation
post 146 that extends through an opening 148 (FIG. 6) of the
respective spring plate 140 to allow for actuation of the
respective tactile switch 134 on the printed circuit board 135 when
the button is pressed.
[0027] As shown in FIG. 6, each spring tree 132 comprises a frame
portion 150 that surrounds the perimeter of the spring tree. The
spring plates 140 are each attached to the frame portion 150 via
two cantilevered spring arms 152. When one of the buttons 112 is
actuated, the spring arms 152 allow the respective spring plate 140
to pivot with respect to the frame portion 150, such that the
actuation post 146 of the button may actuate the respective tactile
switch 134 on the printed circuit board 135. The spring trees 132
also comprise U-shaped springs 154 that are attached to the spring
plates 140 on the sides opposite the cantilevered spring arms 152.
The U-shaped springs 154 operate to reduce audible "twang" (i.e.,
noise) when the buttons 112 are actuated.
[0028] The button assemblies 130 are operable to slide into
channels 160 formed in the yoke 120 as shown in FIGS. 3 and 4.
Specifically, the frame portion 150 of each spring tree 132 is
received by a plurality of tabs 162 and supports 164 that extend
from sidewalls 166 of the channels 160. The frame portion 150 of
each button assembly 130 is firmly held in place in the channels
160 by the tabs 162 and the supports 164. According to the
embodiment of the present invention, the button assemblies 130 are
adapted to be inserted into the channels 160 from the top of the
yokes 120. The yokes 120 comprise sloped structures 168 for guiding
the frame portion 150 of the spring tree 132 to be received between
the tabs 162 and the supports 164. Each button assembly 130 may be
pushed in a downward direction, such that the spring tree 132
slides through the channel 160 until the button assembly is fully
installed on the keypad device 100.
[0029] The spring trees 132 of the button assemblies 130 each
further comprise snaps 170 that operate to hold the buttons
assemblies in place in the channels 160 of the yoke 120. Each snap
170 comprises a snap opening 172 that is adapted to be coupled to a
snap tab 174 formed in the yoke 120. The snaps 170 are each
connected to the frame portion 150 of the respective spring tree
132 via cantilevered snap spring arms 175. When one of the button
assemblies 130 is inserted into the respective channel 160 and
pushed in the downward direction, a bottom edge 176 of the snap 170
contacts a sloped surface 178 of the respective snap tab 174. As
the button assembly 130 is pushed down, the snap 170 pivots about
the snap spring arms 175 and the snap translates across the sloped
surface 178 until the snap tab 174 is received into the snap
opening 172. When the snap tab 172 is received in the snap opening
172, an end surface 179 of the snap tab contacts the bottom edge of
the snap opening, such that the button assembly 130 is locked in
place.
[0030] The yoke 120 further comprises biasing members 180, which
are pivotably coupled to one of the sidewalls 166 of each of the
channels 160. Each biasing member 180 contacts a bottom surface 182
of the spring tree 132 to push the button assembly 130 in a upward
direction, such that the bottom edge of the snap opening 172
contacts the end surface 179 of the snap tab 174. Accordingly, the
button assembly 130 is firmly held in place by the biasing member
180 and the end surface 179 of the snap tab 174. The biasing member
180 also operates to reduce audible twang when the buttons 112 are
actuated.
[0031] To remove one of the button assemblies 130 from the keypad
device 100, the snap 170 lifts away from the yoke 120 as the button
assembly is pulled in the upward direction, such that the snap
pivots about the snap spring arms 175 and the snap opening 172 is
decoupled from the snap tab 174. The button assembly 130 may then
be pushed in the upward direction, such that the snap opening 172
moves over the end surface 179 of the snap tab 174. Accordingly,
the spring tree 132 may then slide through the channel 160, such
that the button assembly 130 may be removed from the keypad device
100.
[0032] The yoke 120 further comprises extensions 184 that protrude
from the side walls 166 of the channels 160. FIG. 8A is a
perspective cross-sectional view of the yoke 120, and FIG. 8B is an
enlarged section of the perspective view of FIG. 8A showing one of
the extensions 184 in greater detail. The extensions 184 extend
from the supports 164 of the yoke 120 (in a direction away from the
front of the keypad device 100), such that each extension has a
height h (as shown in FIG. 8B) that is greater than the thickness
of the spring trees 132. FIG. 9A is a perspective cross-sectional
view of the yoke 120 with the button assemblies 130 installed, and
FIG. 9B is an enlarged section of the perspective view of FIG. 9A.
The extensions 184 are appropriately thin, such that the frame
portions 150 of the spring trees 132 break through the extensions
when the button assemblies 130 are inserted into the channels 160
as shown in FIG. 9B. Accordingly, the spring trees 132 become
wedged between the remaining portion of the extensions 184 and the
supports 164 of the yoke 120 (with tighter tolerances than with
which the spring trees are received between the tabs 162 and the
supports 164). The extensions 184 operate to hold the button
assemblies 130 in place and to further reduce audible twang when
the buttons 112 are actuated.
[0033] While the present invention has been described with
reference to the wall-mounted keypad device 100, the removable
button assemblies 130 could be used on other control devices of the
load control system, such as, for example, wall-mounted dimmer
switches, motor control units, multi-zone load control units, or
table-top keypad devices or load control units.
[0034] Although the present invention has been described in
relation to particular embodiments thereof, many other variations
and modifications and other uses will become apparent to those
skilled in the art. It is preferred, therefore, that the present
invention be limited not by the specific disclosure herein, but
only by the appended claims.
* * * * *